Lens



FIG. 1 is a perspective view of a lens showing the new design;

FIG. 2 is a front view thereof, the rear view, right side view and left side view being identical to the front view;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a cross-sectional view taken along line 5—5 in FIG. 2; and,

FIG. 6 is a reference view thereof showing the lens applying to a light source.

The broken lines form no part of the claimed design. 

The ornamental design for a lens, as shown and described. 